Influence of Reaction Conditions on the Rearrangement of Tetrahydrodicyclopentadiene to Adamantane over Metals Supported on Rare-earth-exchanged Y-Zeolite

Abstract

In the conversion of tetrahydrodicyclopentadiene(TCD) with a bifunctional catalyst, the rearrangement of TCD to adamantane(AdH) and hydrocracking to ring cleavage were found to occur. The dependency of selectivity for adamantane on the reaction conditions were investigated with a fixed bed reactor in the presence of (Pt+Re+Co)/RE-Y catalyst, hydrogen and hydrogen chloride. Two reactions, the rearrangement and hydrocracking, proceed simultaneously (Fig.1). Both were first-order reactions with respect to the concentration of TCD. The dependency of the rate constant of the rearrangement on hydrogen pressure was observed to be a negative order(n=-0.13) (Fig.3). As for the dependency on hydrogen chloride concentration, it was observed that the order of the rearrangement (n=0.3) was higher than that of the hydrocracking(n=0.15) (Fig.4). From the Arrhenius plots, the apparent activa. tion energy of the rearrangement (E₁=119 kJ·mol^-1) was noted to be higher than that of hydrocracking (E₂=107 kJ·mol^-1).